I often hear it from the antiGMO crowd that farmers like to drench their GMO crops in Roundup. Why would farmers buy GMO seed if this means that in turn they need to spend more on pesticides?

Expert response from Lawson Mozley

Sixth Generation Farmer, Master’s Student, Agronomy, University of Florida

Friday, 04/09/2015 13:14

First, let’s talk about the uses for glyphosate (the active ingredient in Roundup) on farms. The most common purpose is weed control. In fields that are planted with Roundup Ready crops, we can use Roundup to kill weeds without harming the crop. This allows us to use one herbicide to control almost all weeds that might be present in a field at the time when we spray. 

Now, let’s talk about how we apply herbicides to fields. The term “drenched” has become a very common buzzword recently when talking about pesticide application, and is quite frankly, completely incorrect. For almost all chemicals that farmers apply, we mix a concentrate into water and apply the mixture with a large sprayer (most common). In the case of Roundup PowerMax, this means that we mix 0.4-32 fluid ounces of Roundup into 20 gallons of water per acre. For perspective, this is between about 2 and half teaspoons to a quart milk bottle per acre, which is approximately the size of a football field, mixed into about as much water as a small SUV gas tank would hold. We then apply this amount to the area of a football field, which means that this wets the plants just enough to sparkle as light reflects on the water droplets, probably less moisture than you see when you clean your kitchen counters with Lysol.

The way that farmers use Roundup is far from drenching, and because of its broad application to many weed species, it actually allows us to apply a smaller number of herbicides in less applications. Additionally, since it is no longer under patent, there are many generic formulations on the market, making both the Roundup brand and the generic glyphosate products cheaper to use due to competition, similar to the way medications get cheaper once generic brands become available.

Farmers buy GMO seeds because they actually allow us to spend much less on pesticides because of the specific traits that those seeds carry. Though the seeds themselves may be more expensive than non-GM alternatives, GM seeds allow us to use fewer, safer, and cheaper chemicals than we often have to use with conventional seeds.